Wednesday, July 6, 2016

Summary



The completed boat BW


A Summary of Building the Boat BW

Having built nine stitch-and-glue boats, I decided to build a tenth and I decided to design my own boat using a one-quarter scale model and computerized drafting.

See Building BW Scale Model for more details

With the design complete, I compiled a list of materials. As far as wood, there are only two types of wood in the BW – Hydrotek BS-1088 meranti plywood and clear pine.

Meranti sheets layed out for matching


Hydrotek BS-1088 stamp

See this blog for more details
Meranti and Moose


The meranti plywood is not stocked locally but the quantities are easily estimated so ordering and shipping went smoothly. The clear pine is available at the local DIY store but finding pieces that are not damaged, have minimal warp and are attractive, is difficult. Instead of buying all of the pine at once, I bought a few sticks at a time so I could be picky and get just the right pieces.

One of the challenges in building the BW was limited shop space. Building an 8-foot x 23-foot boat in a 12-foot by 25-foot space was interesting. I knew that once I stitched the hull together, it would occupy all of the shop space leaving no room to fabricate the rest of the pieces. 

I fabricated the bottom panels, transom, side panels, knees, lifting strakes, spray rails and rubrails in advance. After completing each piece, I hung it from the ceiling to make room for more work. With all the pieces hanging from the ceiling, the shop looked like a scene from a horror movie - a jungle of guillotines.


See Biggens Outta Littlens and
Be Sides for more details

With fabrication of the individual pieces complete, it was time to build a boat. The first step was to build the bottom. When I fabricated the bottom panels, I stitched the keel line together. Now it was just a matter of bringing the ½-inch panels down from the ceiling, spreading them open to the desired deadrise along the length, and taping the keel line.

Taping of the keel



At this point, the shape of the keel line is defined and I can fabricate a keel. Sure, stitch-and-glue boats don’t have a “keel” so to speak. Well, this one does. I built it with 2x6 and 2x10 hemfir lumber, joined together with rabbet joints then cut to match the bottom panel keel profile and deck profile. The final keel piece looks like an Nike swoosh stretched to 20 feet long with a maximum depth of 14 inches.

Keel in place

With the keel in place, I installed bulkheads and additional structural members to create flotation chambers and additional connections between the bottom and deck. The keel and five bulkheads on each side create twelve flotation chambers. 

Bulkheads in place


After flipping, the exterior of the keel is taped and the lifting strakes are installed.

Keel tape and lifting strakes



Next step: install the deck. The deck spans from chine to chine, extending past the bottom panels a few inches to create chine flats and is made from a series of ½-inch meranti, with scarf joints. This boat requires five deck panels, plus a few scraps, to complete the deck which provides the lids for the twelve flotation chambers. I installed one deck panel each day, using temporary clamping screws to hold the panels in place until the epoxy cures. I removed all temporary clamping screws, during the entire build process so that there are no metal fasteners in the boat. 

Installing deck panels


After all of the deck panels were installed, the edges of the deck were trimmed to the final dimension, with a 20° angle to match the side flare.

Trimming deck panels



Now this boat looks like a giant surf board. 



See Another lovely bottom for more details

In order to provide support for the side panels, I installed the transom and some transom knees for extra support of the future outboard motors.



Here comes the fun part. I lowered the side panels down from the ceiling, positioned them and stitched them to the transom and deck. The side panels were pre-drilled for stitching and the stem was stitched before hanging the side panels from the ceiling. Temporary spreaders were installed to get the side panels to their final shape and the interior joints were epoxied and taped with biaxial fiberglass. Typical of stitch-and-glue - after the epoxy cures, remove the stitches.



Twenty-two knees, eleven per side, were epoxy-glued to the inside of the side panels for connection to the future sheer deck. The sheer deck is comprised of a layer of ½-inch ACX plywood covered by a layer of 3/8-inch meranti. The sheer deck was installed proud of the knees and side panels then cut and sanded flush with the knees and side panels.


I installed the inwhale and rubrail with the top edges proud of the deck. The top edges of the inwhale and rubrail were then cut and sanded flush with the sheer deck. The cut edges of the inwhale and rubrail were rounded and covered with fiberglass set in epoxy.




The spray rails were installed and the side panels and the boat was flipped.

Spray rails

Flipping
See Hully Cow for more details

After flipping the boat, the exterior chine joints are epoxied and taped with biaxial fiberglass and the bottom and side panels are completed by painting the bottom and varnishing the side. The bottom cannot be finished bright because the heavy biaxial fiberglass tape at the chines is opaque. The paint extends up the side as needed to cover the biaxial tape and fairing. The rest of the side panel is finished bright with varnish.





Time for another flip

Flipping her back upright

Now the boat can be completed

Rear bench seat

Forward locker

Slop well
For more details see The Last 10%

Build the pilothouse center console, put her on a trailer and install the motors and controls




See Pilothouse Console for details








Launch her and go for a ride!




Same location...



...different build...

...25 years later



Other blogs by Mo 'Poxy










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